DHT11 Sensor Monitoring System

A project that utilizes a DHT11 sensor to measure temperature and humidity and provides real-time monitoring and alerts. The project includes a web frontend built with Angular, a Node.js server, and integration with Azure services for data processing and notification.

Description

The DHT11 Sensor Monitoring System allows you to monitor temperature and humidity readings from a DHT11 sensor in real-time. The system consists of four main components:

1. Frontend: A web application built with Angular that provides an interface for selecting devices and viewing their measured data.

2. Server: A Node.js server that acts as an intermediary between the frontend and the sensor. It handles requests from the frontend, retrieves data from the sensor (via Azure), and provides APIs for accessing device information and data.

3. Azure Integration: The system integrates with Azure services for data processing and notifications. It utilizes Azure Service Bus Topics for publishing sensor data to specific topics and Azure Logic Apps for email notifications.

4. Arduino UNO with DHT11 sensor: For measuring temperature and humidity. Since Arduino UNO does not have built-in WiFi capabilities it uses Serial communication to send data to the PC via COM4 port to the helper script that forwards the data to the cloud.

The project enables you to visualize sensor data, track historical trends, set thresholds for alert notifications, and receive email alerts when the temperature or humidity exceeds the defined thresholds.

Features

• Real-time monitoring of temperature and humidity readings
• Select and view data from multiple devices
• Data visualization through charts
• Periodic data storage in JSON files for every device
• Threshold-based alert system for high temperature or humidity levels integrated with Azure services for scalable data processing and notifications

Installation

1. Clone the repository from GitHub.
2. Install the necessary dependencies for the frontend and server using npm.
3. Set up the Azure services (Service Bus, Logic Apps).
4. Configure the publisher (arduino) and server to connect to the appropriate Azure resources by updating the configuration files with the required connection strings.

Usage

Create Azure Service Bus, select standard pricing so you can create topics. Create topics "humidity" and "temperature" and "arduinoalert" for each topic create a subscription. Create a config.js file in root directory where you write your connection string for Service Bus and Subscription name. Should be in format:

module.exports = {
    connectionString:"<YOUR-CONNECTION-STRING>",
    subscriptionName: "<YOUR-SUBSCRIPTION-NAME>",
}

(OPTIONAL) Create new topic "alert" and Azure Logic App that will be responsible for sending emails. It should look like this.

Connect arduino with DHT11 sensor to the PC, start helper script

node .\sensor\publisher.js

Start the server

node .\backend\server.js

Launch the frontend in the frontend directory

ng serve

Access the frontend in your web browser to see device/s and data. Monitor the charts and receive email alerts when the thresholds are exceeded.

Architecture - data flow

Technologies and services

The project utilizes the following technologies and services:

• Angular: Frontend web application framework
• Node.js: Server-side and publisher(arduino) runtime environment
• Express.js: Web application framework for the server
• Azure Service Bus: Messaging service for publishing sensor data and triggering alerts
• Azure Logic Apps: Workflow automation and email notification system
• DHT11 Sensor library for arduino + Temperature and humidity sensor